This invention is concerned with gas-pressurized systems. More particularly, it is concerned with a safe and reliable gas-pressurized system where the oxidizer and fuel for a hypergolic reaction must be introduced into a combustion chamber simultaneously.
The system is used in a rocket-powered target drone which is fueled by a storable liquid bipropellant. The bipropellant is composed of an oxidizer, such as inhibited red fuming nitric acid (IRFNA), and mixed amine fuel (MAF). These substances are stored in separate tanks in the drone, and react hypergolically when simultaneously introduced into the rocket's combustion chamber. When it is desired to fire the rocket motor, high pressure nitrogen is sent through a standpipe into each tank to force the two substances into the chamber.
The shelf life, and the actual safety of these drones is limited by the destructive reaction of the oxidizer's distillates on the gas-pressurizer in the IRFNA tank. Prior art gas pressurizers use a gold diaphragm to separate the end of the pressure standpipe and the oxidizer, and the acid formed by the distillation of the IRFNA corrodes this diaphragm. The acid enters the standpipe and reacts destructively with it. The corrosive reaction detracts from drone performance. In extreme cases, the acid can cause a leak to develop in the pressurizing gas flow pipe, which could allow the IRFNA to prematurely combine with the fuel and ignite outside the combustion chamber.